A device for providing a vapor, comprising one or more finely porous foam bodies which are brought to a vaporization temperature by passing an electrical current through them, is disclosed in WO 2012/175124, DE 10 2011 051 261 A1 or DE 10 2011 051 260 A1. These documents state, inter alia, that due to the non-uniform particle size it is advantageous to thinly coat the cell walls of an open porous foam body with the aerosol, so that due to heat supplied through the coated cell walls, the coating can be uniformly evaporated.
WO 2012/175128 or WO 2012/175126 describe a vaporization device and a vaporization method in which a vapor is brought into a multi-stage temperature control device. In the upstream temperature control stage the vapor, or the carrier gas carrying the vapor, is heated to a homogeneous temperature. This takes place in an open porous foam body which is heated up to such a temperature that the vapor does not condense on the cell walls of the foam body. A second porous foam body arranged downstream has a lower temperature, so that the vapor can condense there on the cell surfaces. The downstream temperature regulation stage is held at a temperature at which condensation and evaporation are in equilibrium, so that averaged over time no accumulation of a non-gaseous substance is formed on the cell walls.